Steam-boiler furnace



1 t D V e h s t e e S 2 N A L L I M G M u M d 0 M 0 m STEAM BOILERFURNACE.

R K m, M J is M W. m, Q m sw m? w *\\Q H R o\ w w w m zi: M M W m vi h Mw v w M \w \Y \W \T e .l a! .IIVI \Y i 00000- Mi Q 0000000 Q. 0000000 &i 000000000 0. 000000000 my 0 000000000 5. m Nwn wfi fl (No Model.) 2Sheets-Sheet 2.

J. McMILLAN. STEAM BOILER FURNACE.

No. 519,267. Patented May 1, 1894.

-74 O 7T/GSSES F lame'czflo d zi/amfi, fi W w wAsnmeToN. u. 04

have invented certain UNITED STATES ATENT Erica.

JAMES MOMILLAN, OF CHICAGO, ILLINOIS.

STEAM-BOILER FURNACE.

SPECIFICATION forming part of Iletters Patent No. 519,267, dated May 1,1894- Application filed January 8, 1894.

To alt whom it may concern:

Be 1t known thatI, JAMES MCMILLAN, a citizen of the United States,residing at Chicago, n the county of Cook and State of Illinois,

new and useful Improvements in Steam-Boiler Furnaces; and I do declarethe following to be a full, clear, and exact description oftheinvention, such as W111 enable others skilled in the art to which itappertains to make and use the same, reference being had to theaccompanying drawings, and to the letters of reference marked thereon,whlch form a partof this specification.

My invention relates to smoke burning steam boiler furnaces.

Its object is to secure the complete combustion of the carbon given offfrom burning fuel while securing the -full benefit of the heat generatedby the burning gases.

The invention has for its further object the protection of the boiler bythe more equal distribution through it of the heat.

The invention consists of the use of an inclosed fire-box located belowthe boiler and separated therefrom by a brick arch and discharging theproducts of combustioninto the combustion chamber through flues in abridge wall of great thickness.

In the accompanying drawings, Figure 1, is a transverse vertical sectionof the furnace. F g. 2, is a plan section on the line 22 of Flg. 1. Fig.3, is a vertical longitudinal sec t1on on the line 3-3 of Fig. 1. Fig.4, is a plan section on the line 4=-el of Fig. 1.

In order to secure complete combustion it 1s necessary that a hightemperature'of the dlstilled gases be maintained. This is foundexceedingly d ifficult of accomplishment when the roof or top of thefire-box is the crown 4o sheet of the boiler, as the water isnecessarily of lower temperature than the burning gases and as theyimmediately come in contact with the boiler in the old style ofconstructlon, they are chilled to such an extent that 5 theirinflammation is checked and acloud of black smoke can be plainly seenrollingback to the flue. Furthermore it is necessary to provide notmerely a supplemental supply of oxygen to complete the combustion of thegases, but means must be supplied not only for preventing the loweringof the temperature by the natural radiation, but for actu- SerlalNo.496,103- (No model-l ally raising it and for heating the supplementalair supply. The difficulties enumerated are overcome in my'improvedfurnace and the purposes set forth above are subserved in the mannerhereinafter described.

For the purpose of clearness I have shown in the accompanying drawingsthe major features of an ordinary steam boiler furnace, comprising theboiler, A; the grate bars, 13, the furnace front, C, and its side walls,a, and the feeding doors, D. The bridge wall, E, is of unusualthickness, being preferably not less than three feet thick. Its centerreaches to the boiler and its upper surface is curved in arch form. Asolid arch, E, that is an arch without perforations of the same heightas through the bridge wall; a multiple numberof flues, c, of amplecapacity being provided for this purpose. A supplemental air supply isprovided for by means of ducts G, G, extending through the side-walls,c, c, and thence through the bridge wall below the apertures e,discharge ports into the fire-box beingprovided, one directly below eachof the apertures e, as shown at II. By this construction the air isintroduced into the furnace already well heated and immediately itmingles with the burning gases as they enter the fines in the bridgewall. The front wall, C, of the furnace is closed tightly around thefront end of the boiler, A. Chambers, a, a, are formed by theconstruction described upon each side of the boiler andabove the arch,F, of the fire-box, these chambers being open at their rearward end andclosed at their-forward end so that there is no draft through them andthe heat from the arch, F, which becomes very intense, is radiated tothe boiler. When the furnace is in use the arch,F,quickly becomes heatedto a high degree so that the gases distilled from the fuel are notcooled by contact with it, on the contrary its temperature issufficiently high to stimulate combustion. The same is true of the wallsof the apertures, 6. These apertures, or flues, serve the purpose, infact, of retorts, and all the conditions essential to perfect combustionare present; namely, combustible gases, an

ample supply of oxygen and high temperature, and there issues from theseretorts a perfectly White flame,giving off an invisible vapor. Bypreventing contact of the vapors "resulting from combustion with thecomparatively cool surface of the boiler until their combustion hasbecome complete, perfect combustion is made possible; furthermore, theboiler itself is protected from the constant variations of temperaturedue to the exposure of its surface to the direct action of the flames,the heatfrom the arch being uniform and the combustion at the rear ofthe bridge Wall being substantially without variation. I claim as myinvention a 1. A steam boiler furnace having its firebox completelyinclosed by masonry, and having discharge flues in tubular form and ofsuch capacity as to secure free draft and insure complete combustionwithin the fines leading from its fire-box through such masonry,substantially as described and for the purpose specified.

2. In a steam boiler furnace the combination of a grate, side walls, asolid arch c0vering the fire-box, a bridge wall extending to, andjoining the rear end of the arch, and fiues, in tubular form leadingfrom the firebox through the bridge wall aud of such capacity as tosecure free draft and insure complete combustion within the fines, substantially as described and for the purpose specified.

3. In a steam boiler furnace the combination with a boiler, of afire-box, an arch, F, covering the fire-boxand separating it from theboiler, and a bridge wall extending to the arch and having flueopenings, 6, e, leading outwardly from the fire-box, and air ductsleading from without the furnace and opening to the fire-box below theflue openings, 6, e, said bridge wall being of such thickness that theflue openings serve the purpose of retorts, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

JAMES MOMILLAN.

Witnesses:

JOHN F. MIOHALSKI, Louis K. GILLsoN.

